Apparatus for forcibly propelling pellets against a surface



DEC. 16, 1952 P|ETY 2,621,351

APPARATUS FOR FORCIBLY PROPELLING PELLETS AGAINST A SURFACE Filed Aug. 30, 1948 2 SHEETS-SHEET 2 MAGNETICALLY 2 OPERABLE SWITCH INVENTOR.

R. G, PIETY ATTORNEYS Patented Dec. 16, 1952 APPARATUS FOR FORCIBLY PROPELLING PELLETS AGAINST A SURFACE Raymond G. Piety, Bartlesville, kla., assignor to Phillips Petroleum Company, a corporation of Delaware Application August 30, 1948, Serial No. 46,821

10 Claims. 1

This invention relates to apparatus for forcibly propelling pellets of hard material against a surface, such as the walls of a bore hole or pipe line, to clean or scour the same. In another aspect, it relates to such apparatus wherein the pellets are propelled by an implosion resulting from a sudden flow or surge of fluid under pressure into a chamber having a relatively lowinterior pressure.

It is oftentimes necessary to remove filter cake or other deposits from the interior of a bore hole or pipe line. In the case of a bore hole, this may be done to permit the surface of the bore hole to be photographed, or in order to facilitate tests of a portion of the bore hole to determine production possibilities. The pellets may also be used to increase the flow of oil from an adjacent formation into a well. In the case of a pipe line, deposits of material may be removed from the inner surface of the pipe which obstruct the flow of liquid therethrough. I

It is an object of this invention to provide improved apparatus for removing filter cake or other deposits from the interior of a bore hole or pipe line.

It is a further object of the invention to accompli'sh this purpose by utilizing fluid pressure in the well or pipe line to produce an implosion and thereby force pellets of hard material against the walls of the bore hole or pipe line to remove obstructions therefrom.

It is a still further object of the invention to provide such apparatus at a low cost, and to produce a tool of rugged construction which is reliable in operation and which does not require skilled operators, and eliminates danger and hazard resulting from the handling of explosives.

Various other objects, advantages and features of the invention will become apparent from the following detailed description taken in conjunction with the accompanying drawings, in which:

Figure 1 is a vertical sectional view of a bore hole showing the construction of my novel implosion tool;

Figure 2 is a sectional view taken along the lines 2--2 of Figure l;

Figure 3 is a sectional view of a modified form of the tool which is particularly suitable for use in a pipe line;

Figure 4 is a sectional view illustrating a trigger device for producing the implosion; and

Figure 5 is a sectional view showing a modified form of trigger construction.

Referring now to the drawings in detail, and particularly to Figures 1 and 2, I have shown an embodiment of the apparatus which is particularly suitable for removing filter cake or other obstructions from bore holes. This apparatus comprises an elongated generally cylindrical casing l0 having a combined weight and guide member H secured to the lower end thereof. This member has a generally conical upright portion I2 for properly directing the force of the implosion, as will be hereinafter described in detail. A frangible disc or wall 13, which is seated against a lock ring M, divides the interior of easing I0 into a pellet container l5 and a relatively large implosion chamber I6. 7

The container portion I5 is filled with pellets H of hard material, which is preferably frangible, and these pellets support the frangible wall I3 in its seated position against lock ring M. The pellets [1 may advantageously consist of heat treated glass marbles. However, other hard materials may be used and the pellets need not necessarily be of spherical shape, although this is desirable to prevent packing of the pellets within the chamber.

A section of container 15 is defined by a ring [9 of frangible material which is preferably positioned at the bottom of the casing adjacent the weight member II. Rods or braces 20 connect the weight H and the metal casing 10 to provide a strong mechanical structure.

The implosion chamber I6 is defined by the frangible wall IS, the casing 10, and a second wall or disc 22 of frangible material which is held in position by a pair of spaced lock rings 23 and 24. The outer surface 25 of frangible disc 22 is exposed to the pressure of fluid 26 in the bore hole and, at a considerable depth, the pressure upon the surface 25 is far greater than the pressure within the chamber [6. The disc 22 is of sufiicient strength that it is not fractured by this pressure differential when it is supported at its center. However, when it is not supported at its center, the pressure differential is sufiicient to fracture the disc and allow the fluid 26 to rush or surge into the chamber [6.

The disc 22 is normally supported at its center by a rod 21, one end of which has a hooked portion engaging an eyelet 28, at the central region of the disc. The other end of rod 21 has a hooked portion which is normally engaged by a latch 29, this latch being actuated by a solenoid 30 mounted within a sealed box or enclosure 3|. This box is secured to the casing by a supporting member 32 which is screw threaded to the casing Ill and which is provided with large openings 33 to permit the well fluid to contact the surface 25 of the disc 22. The box 3! is also provided with an eyelet 35 so that the tool may be raised and lowered in the bore hole by a cable 35. The circuit for actuating solenoid 33 is schematically shown as a pair of conductors 35, 3? connected in circuit with a battery 33 and a switch 3E. In practice, of course, the conductors 35, 3'! are contained in the cable 35 so that the solenoid may be actuated from the top of the well.

The operation of the disclosed apparatus will now be apparent to those skilled in the art. Assuming that the tool is lowered to a considerable depth in a bore hole, the pressure of fluid 25 will be substantially higher than the pressure within implosion chamber l5. However, breakage of frangible disc 22 will be prevented by rod 2'! which is held in locked position by latch 29 and supports the central part of the frangible disc. The tool is then moved to a position wherein ring is is adjacent an encrustation of filter cake ll or other substance which it is desired to remove from the bore hole. Thereupon, solenoid 39 is actuated and latch 29 is released from engagement with rod 27, thereby removing the support from the central region of disc 22. As a result, disc 22 is fractured and the fluid 2b rushes into the implosion chamber I6 and strikes frangible disc l3 with a sharp impact.

It will be noted that disc I3 is substantially thinner than disc 22 which, in turn, is thinner than frangible ring 19. Accordingly, disc I3 ofiers little resistance to the impact of the inrushing fluid and the force of the fluid is transferred to the pellets ll, causing fracture of ring I9 and forcibly propelling the pellets against the material ll. In this connection, it will be noted that the conical projection 52 guides the pellets in a lateral direction through the opening left by the fractured ring i9. That is, the guide l2 transforms the force of the implosion, which is propagated primarily in a downward direction, into a lateral force tending to move the pellets sideways and eject them against the material 3! at the sides of the bore hole. It is important that frangible ring I9 be thicker than disc 22 so that the ring is not fractured by the pressure differential between the interior and exterior of easing although, of course, ring is is readily fractured by the force resulting from the impact of the inrushing fluid against disc 3 and pellets H.

The pellets are very effective in scrubbing filter cake or other formations from the walls of a bore hole and, where the apparatus is lowered to a considerable depth, the force imparted to the pellets may be so great as to enable the apparatus to be used in perforating oil well casings. The force with which the pellets are ejected depends to a great extent upon the size of implosion chamber It. The larger the chamber, the greater is the kinetic energy of the inrushing fluid and the greater the force imparted to the pellets by the impact or" the fluid against disc [3.

In the modification of the invention shown by Figure 5, the triggering mechanism 27, 29 is omitted and frangible disc 22 is made of sufficient strength as to withstand the pressure differential between the interior and exterior of the implosion chamber. A solenoid 43 is disposed centrally of the enclosure 3! and this solenoid has an elongated armature it terminating in a puncture member 45 which is closely spaced to frangible disc 22, the puncture member being biased to such closely spaced position by a spring 46. When the 4 solenoid is energized, puncture member 55 strikes disc 22 and fractures it, thereby initiating an implosion in chamber 15, Figure 1. Solenoid 43 is actuated by current supplied through leads 4'], 28 which are connected in a circuit similar to that disclosed by Figure l.

The apparatus of this invention is not restricted to use in cleaning filter cake or other deposits from bore holes. For example, the tool may be utilized in the manner shown by Figure 3 to clean out deposits from pipe lines, and for various other purposes. The structure of the implosion chamber of Figure 3 is generally similar to that of Figure 1 and like parts are indicated by the same reference characters. In the modified structure, lock ring 24, support 32, rod 21 and its associated structure are omitted, the lock ring 24 being replaced by a Washer 50. A brush assembly, generally indicated by reference character 5!, is secured to the screw threaded end of easing it, this assembly consisting of two units 52 and 53. each of which has an annular brush 5 mounted on a large annular washer 55. The brushes 54 are adapted to engage the interior surface of a pipe line 51 and each brush is abutted by a resilient washer 58 having a peripheral flanged portion which engages the pipe line and seals the peripheral regions of each brush assembly. The assemblies 52, 53 are supported on a metal sleeve 5% within which is fitted a bolt 66 having a longitudinal interior passage Bl. The head 62 of bolt 66 abuts an exteriorly threaded washer 53 which is screw threaded in the casing H3 and eyelets 64 are provided for holding together the brush assembly 52, these eyelets extending through washer E3, annular member 55, and washer 53. Brush assembly 53 is supported by nuts 65, which hold the washer 58 against sleeve 53, and eyelets 6-1 which extend through washer 58 and annular member 55.

The frangible disc 22 of Figure 3 is of sumcient strength to withstand the pressure differential between the interior and exterior of implosion chamber l 6. This disc is adapted to be fractured by pins 89 which are mounted in the head of bolt 62 in the manner illustrated by Figure 4. It will be noted that each pin 69 is slideably mounted within a recess 79 formed within bolt head 62 and a charge of powder H is packed behind each pin 69. Each charge H is adapted to be detonated by a blasting cap indicated schematically by a heater coil 12. Conductors 13, i4 extend through small passages in the bolt head 62, these conductors connecting all of the blasting caps 12, in series with a battery 75 and a magnetically operable switch '16 mounted in any suitable position within the brush assembly 5i. Switch '16 is operated when a strong electromagnetic field is impressed thereon by an inductor located exteriorly of pipe line 51.

The operation of the modified form of the invention will now be apparent to those skilled in the art. When a pipe line becomes clogged 0r obstructed, the tool is inserted into one end thereof and propelled downstream by the fluid in the pipe line. The direction of travel, in the illustrated example, is from right to left, Figure 3. When the apparatus strikes an obstruction in the pipe line, its movement is stopped and pipe line liquid flowing through eyelets 64, 67 and hollow bolt Gil builds up a large fluid pressure behind frangible disc 22. After it has stopped, the tool is located, by the sound of fluid leaking past the brush assembly 5!. Thereupon, magnetically operable switch it is actuated by generating a strong electromagnetic field about the exterior of the pipe line with the result that explosive charges H are detonated and the pins 69 fracture frangible disc 22. Responsive to the pressure differential between the exterior and interior of chamber H3, an implosion occurs as described in connection with Figure l, causing disc 13 to be fractured and forcibly ejecting the pellets I1 through the space defined by frangible ring I9, after the same is fractured by the force of the implosion.

The pellets are very eiiicient in removing obstructions from the pipe line by the scouring action resulting from engagement thereof with the Walls of the pipe. When the obstruction is removed in this manner, the apparatus is again propelled through the pipe line by the force of the fluid passing therethrough and is removed at the other end of the line or at a predetermined location beyond the point of clogging.

It is will be apparent that the described apparatus is capable of many uses and that many variations therein may be made without departing from the spirit and scope of the invention. The unit is quite economical in operation since the force for driving the pellets against the surface to be treated is supplied by a difference in fluid pressure, rather than by the detonation of a large explosive charge. The pressure-s encountered in pipe lines and bore holes are sufficient to enable eiiicient operation of the device and the scouring action against the surface to be treated is highly advantageous in removing filter cake, or other obstructions therefrom.

While the invention has been described in connection with present, preferred embodiments thereof, it is to be understood that this decription is illustrative only and is not intended to limit the invention, the scope of which is defined by the appended claims.

Having described my invention, I claim:

1. Apparatus for forcibly propelling pellets of hard material against a surface to be treated comprising, in combination, a generally cylindrical vessel having a weight portion at the bottom thereof and having an interior wall of frangible material dividin said vessel into a pellet container and an implosion chamber, pellets of hard material in said container, said pellet container comprising a ring of frangible material forming a part of said vessel, a guide for directing said pellets against said ring, and braces connecting said weight portion with the portion of the vessel above said ring of frangible material, the top of said implosion chamber being defined by a disc of frangible material, the pressure on the exterior of said disc being substantially greater than the pressure within said implosion chamber, and means for fracturing said frangible disc.

2. Apparatus for forcibly propelling pellets of hard material against a surface to be treated comprising, in combination, a generally cylindrical vessel having a weight portion at the bottom thereof and having an interior wall of frangible material dividing said vessel into a pellet container and an implosion chamber, pellets of hard material in said container, said pellet container com-prising a ring of frangible material forming a part of said cylindrical vessel adjacent said weight portion, a, guide for directing said pellets against said ring, and braces connecting said weight portion with the portion of the vessel above said ring of frangible material, the top of said implosion chamber being defined by a disc of frangible material, the pressure on the exterior of said disc being substantially greater than the pressure within said implosion chamber, a rod having one end thereof secured to the central region of said frangible disc, a solenoid,

a latch actuated thereby for normally supporting the other end of said rod to prevent breakage of said disc, and means for operating said solenoid to release said latch, whereby said frangible disc is broken due to the pressure differential between the interior and exterior of said implosion chamber.

3. Apparatus for forcibly propelling pellets of hard material against a surface to be treated comprising, in combination, a generally cylindrical vessel having a weight portion at the bottom thereof and having an interior wall of frangible material dividing said vessel into a pellet container and an implosion chamber, pellets of hard material in said container said pellet container comprising a ring of frangible material forming a part of said cylindrical vessel adjacent said Weight portion, and braces connecting said weight with the portion of the vessel above said ring of frangible material, the top of said implosion chamber being defined by a disc of frangible material, the pressure on the exterior of said disc being substantially greater than the pressure within said implosion chamber, a solenoid having an extended armature, a pointed member at the end of said armature which is engageable with said frangible disc, means for biasing said armature to a portion spaced from said disc, and means for actuating said solenoid to force said pointed member into engagement with said disc, thereby to fracture the same.

4. Apparatus for forcibly propelling pellets of hard material against a surface to be treated comprising, in combination, an elongated generally cylindrical casing, means for propelling said casing through a pipe as a, unit by fluid pressure in such pipe, a frangible wall in said casing dividing it into a pellet container and an implosion chamber, said container being filled with pellets of hard material, and bein defined in part of a ring of frangible material, guide means for directing said pellets against said ring when an implosion occurs in said chamber, a second wall of frangible material forming a part of said implosion chamber, means permitting fluid under pressure to pass to the outer surface of said second frangible wall, whereby the pressure interiorly of the implosion chamber is substantially lower than the exterior pressure, and means for fracturing said second frangible wall to cause an implosion in said chamber, thereby to fracture said first frangible wall and said frangible ring with resultant ejection of said pellets through the fractured ring.

5. Apparatus for forcibly propelling pellets of hard material against a surface to be treated comprising, in combination, a pair of brush assemblies each including an annular brush having a resilient gasket secured thereto of substantially the same diameter as said brush, an annular support mounted interiorly of each brush, a unit comprising a hollow bolt for holding said brush assemblies in parallel spaced arrangement, an elongated generally cylindrical casing having one end thereof secured to one of said brush assemblies and having an inwardly protrudin conical guide portion at its other end, a ring of frangible material forming a part of said casing adjacent said guide portion, pellets of hard material in said casing adjacent said ring of franible material, braces extending from the guide portion to a region of the casing adjacent said frangible ring, a pair of spaced discs of frangible material mounted within said casing, one disc holdin said pellets adjacent said ring, one of said discs being mounted at the end of said casing adjacent said brush assemblies, the other disc engaging said pellets to hold them in contact with said ring, and means for fracturing the frangible disc adjacent said brush assemblies.

6. Apparatus for forcibly propelling pellets of hard material against a surface to be treated comprising, in combination, a pair of brush assemblies each including an annular brush hav- 'ing a resilient gasket secured thereto of substantially the same diameter as said brush, an annular support mounted interiorly of each brush, a unit comprising a. hollow bolt for holding said brush assemblies in parallel spaced arrangement, an elonagted generally cylindrical casing having one end thereof secured to one of said brush assemblies and having an inwardly protruding conical guide portion at its other end, a ring of frailgible material forming a part of said casing adjacent said guide portion, braces extending from the guide portion to a region of the casing adja cent said frangible ring, a pair of spaced discs of frangible material mounted within said casing, pellets of hard material disposed in said casing between said ring and one of said discs, the other disc being mounted at the end of said casing adjacent said brush assemblies, a puncture member mounted in the head of said bolt and adapted for engagement with the frangible disc adjacent said brush assemblies, said member being movable longitudinally within a, passage formed in said bolt head, a charge of explosive material in said passage, a blasting cap for detonating said material, and means including a battery and a magnetically operable switch for actuatin said blasting cap.

7. Apparatus for forcibly propelling pellets of hard material against a surface to be treated comprising, in combination, a generally cylindrical vessel having an interior wall of frangible material dividing said vessel into a. pellet container and an implosion chamber, pellets of hard material in said container, said pellet container comprising a ring of frangible material forming a part of said vessel, a guide for directing said pellets against said ring, and braces connecting said guide with the portion of the vessel above said ring of frangible material, one end of said implosion chamber being defined by a disc of frangible material, the pressure on the exterior of said disc being substantiall greater than the pressure within said implosion chamber, and means for fracturing said frangible disc.

8. Apparatus for forcibly propelling pellets of hard material against a surface to be treated comprising, in combination, a generally cylindrical vessel having an interior wall of frangible material dividing said vessel into a pellet container and an implosion chamber, pellets of hard material in said container, said pellet container comprising a ring of frangible material forming a part of said cylindrical vessel, a guide for directing said pellets against said ring, and braces connecting said guide with the portion of the vessel above said ring of frangible material, one end of said implosion chamber being defined by a disc of frangible material, the pressure on the exterior of said disc being substantially greater than the pressure Within said implosion chamber, a rod having one end thereof secured to the central region of said frangible disc, a solenoid, a latch actuated thereby for normally supportin the other end of said rod to prevent breakage of said disc, and means for operating said solenoid to release said latch, whereby said frangible disc is broken due to the pressure differential between the interior and exterior of said implosion chamber.

9. Apparatus for forcibly propelling pellets of hard material against a surface to be treated comprising, in combination, an elongated vessel, pellets of hard material positioned at one end of said vessel, a frangible member defining a portion of the side wall of said vessel, said frangible member being in contact with said pellets, means for directing said pellets against said frangible member in a lateral direction, a piece of frangible material closing the otherend of said vessel, said piece of frangible material being spaced from said pellets to define an implosion chamber, the pressure on the exterior of said piece of frangible material being substantially greater than the pressure within said implosion chamber, and means for fracturing said piece of frangible material.

10. Apparatus for forcibly propelling pellets of hard material against a surface to be treated comprising, in combination, an elongated, generally cylindrical vessel, pellets of hard material positioned at one end of said vessel, a frangible member defining a portion of the side wall of said vessel adjacent said pellets, a guide secured to and closin the lower end of said vessel, said guide having a generally conical upright portion for directing said pellets against said frangible member in a generally lateral direction, a piece of frangible material closing the other end of said vessel, said piece of frangible material being spaced from said pellets, and means for fracturing said piece of frangible material.

RAYMQND G. PIETY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 422,347 Hyde Feb. 25, 1890 1,895,563 Armstrong Jan. 31, 1933 2,263,774 Heltzel et a1. Nov. 25, 1941 2,283,300 Vincent May 19, 1942 2,455,556 Burch Dec. 7, 1948 

